SynthesisCanadian respiratory journal2020

Association of Metformin Use with Asthma Exacerbation in Patients with Concurrent Asthma and Diabetes: A Systematic Review and Meta-Analysis of Observational Studies.

Li Wen, Wang Zhong, Yihui Chai, Qin Zhong, Jie Gao, Liancheng Guan, Zhang Mengzhi, Liu Huaiquan, Yu Haiyang, Wang Qingxue and 2 more

Open access · goldFull text readMeta-AnalysisSystematic Review
In one paragraph

Synthesis in Canadian respiratory journal, 2020. The graph read 1 number from its abstract, feeding 1 cell of the map, but none could be read as for or against, so it casts no vote. Cited by 13 papers, 2 of them syntheses that pooled it.

1number the graph read from it
0cells of the map it votes in
13citing papers in PubMed, 2 pooled it
1.0field-weighted citation impact, top 26% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

Read, but not usablea number the graph found but could not read as for or against

Costs & health-care usean association or prognostic statement, not a treatment comparison · t2dfeeds one cell of the map
OR 0.650.28 to 1.48
The pooled effect size showed that metformin was inversely associated with a risk of asthma exacerbation (OR = 0.65, 95% CI 0.28-1.48; Conclusion: This meta-analysis suggested that metformin decreased the risk of asthma-related emergency room visits for patients with concurrent asthma and diabetes.

clause the extractor read what became the number

2 · Its place on the map

Where it lands on the map

Rows are treatments, columns are outcomes. The coloured squares are the cells this paper feeds, coloured by the vote it casts there. Click one to jump to what this paper adds to it.

supports the treatmentfavours the comparatorno clear differenceread, but no usable result
3 · What it changes

What it adds to each cell

For every cell the paper feeds: the belief in the claim with and without this paper, and this paper's estimate drawn against every other readable study in the cell. The ringed dot is this paper.

Metformin×costs & health-care use

No readable resultOpen on the map →What to test next →

1 readable study in this cell: 0 favour the treatment, 1 find no difference, 0 favour the comparator.

Belief with this paper
0.25no deciding trial · 0 families support, 0 contradict · against placebo
Without itNot a counted family in this claim, so removing it changes nothing.
← favours the treatmentfavours the comparator →
0 · no effect
NCT02980276535 enrolled · 2017
Δ -6.50-13.9 to 12.9

This paper's own estimate is on a different scale from the rest of the cell, so it is not drawn here.

4 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

5 · Its place in the literature

Who cites it

13 citing papers in PubMed, 2 syntheses or guidelines pooled it, 14 citations in OpenAlex.

  1. Pooled it
  2. Pooled it
  3. Review
  4. Metformin for asthma exacerbations.The Cochrane database of systematic reviews · 2026
    Article
  5. Article
  6. Article
  7. Diabetes-inducing effects of bronchial asthma.World journal of diabetes · 2025
    Article
  8. Review
  9. Review
  10. AMPK suppresses Th2 cell responses by repressing mTORC2.Experimental & molecular medicine · 2022
    Article
  11. Metformin and the Development of Asthma in Patients with Type 2 Diabetes.International journal of environmental research and public health · 2022
    Article
  12. Review
  13. Article
6 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

7 · Who and what money

Authors and funding

12 authors at 3 institutions in 1 country.

Li WenSchool of Preclinical Medicine, Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou, China.ORCID 0000-0002-3975-3312
Wang ZhongDepartment of Clinical Nutrition, Chengdu Fifth People's Hospital, Chengdu, Sichuan, China.
Yihui ChaiSchool of Preclinical Medicine, Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou, China.
Qin ZhongSchool of Preclinical Medicine, Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou, China.
Jie GaoSchool of Preclinical Medicine, Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou, China.
Liancheng GuanSecond Affiliated Hospital, Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou, China.
Zhang MengzhiSchool of Preclinical Medicine, Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou, China.
Liu HuaiquanSchool of Preclinical Medicine, Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou, China.
Yu HaiyangSchool of Preclinical Medicine, Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou, China.
Wang QingxueSchool of Preclinical Medicine, Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou, China.
Yang ChangfuSchool of Preclinical Medicine, Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou, China.
Chen YunzhiSchool of Preclinical Medicine, Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou, China.ORCID 0000-0002-4546-5341
Guiyang College of Traditional Chinese Medicine · CNAffiliated Hospital of Guizhou Medical University · CNChengdu Fifth People's Hospital · CN

Funding

No grant is acknowledged in the PubMed record.

8 · The paper itself

Abstract

The marked sentences are the ones the graph read a number from.

Background: Asthma and diabetes are both diseases that affect a wide range of people worldwide. As a common treatment for diabetes, metformin has also been reported to be effective in improving asthma outcomes. We conducted a combined analysis to examine the efficacy of metformin in reducing asthma exacerbation in patients with concurrent asthma and diabetes. Methods: We searched the PubMed, Embase, and CENTRAL databases for articles published prior to April 2020 to find observational studies of individuals with concurrent asthma and diabetes that compared the risk of asthma exacerbation between metformin users and nonusers. Two researchers separately screened the studies, extracted data, and evaluated the risk of bias. The primary outcome was the adjusted risk of asthma exacerbation. The secondary outcomes were the adjusted risk of asthma-related hospitalization and emergency room visits. Review Manager was used for data analysis and plotting. Results: We included two studies with a total of 25252 patients. The pooled effect size showed that metformin was inversely associated with a risk of asthma exacerbation (OR = 0.65, 95% CI 0.28-1.48; Conclusion: This meta-analysis suggested that metformin decreased the risk of asthma-related emergency room visits for patients with concurrent asthma and diabetes. Metformin reduced the risk of asthma-related hospitalization and exacerbation but was not statistically significant. More randomized trials involving larger samples should be considered, and the mechanisms of these effects need to be fully elucidated.

Indexed as

AsthmaDiabetes Mellitus, Type 2Disease ProgressionHumansMetforminObservational Studies as TopicRisk FactorsMetformin

Identifiers

PMID32831980
PMCPMC7424499
OpenAlexW3023569961

What Socratic holds

Textfull text, public
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.